asbestosis

Asbestosis

Definition

Asbestosis is chronic, progressive inflammation of the lung. It is not contagious.

Description

Asbestosis is a consequence of prolonged exposure to large quantities of asbestos, a material once widely used in construction, insulation, and manufacturing. When asbestos is inhaled, fibers penetrate the breathing passages and irritate, fill, inflame, and scar lung tissue. In advanced asbestosis,, the lungs shrink, stiffen, and become honeycombed (riddled with tiny holes).

Legislation has reduced use of asbestos in the United States, but workers who handle automobile brake shoe linings, boiler insulation, ceiling acoustic tiles, electrical equipment, and fire-resistant materials are still exposed to the substance. Asbestos is used in the production of paints and plastics. Significant amounts can be released into the atmosphere when old buildings or boats are razed or remodeled.

Asbestosis is most common in men over 40 who have worked in asbestos-related occupations. Smokers or heavy drinkers have the greatest risk of developing this disease. Between 1968 and 1992, more than 10,000 Americans over the age of 15 died as a result of asbestosis. Nearly 25% of those who died lived in California or New Jersey, and most of them had worked in the construction or shipbuilding trades.

Causes and symptoms

Occupational exposure is the most common cause of asbestosis, but the condition also strikes people who inhale asbestos fiber or who are exposed to waste products from plants near their homes. Family members can develop the disease as a result of inhaling particles of asbestos dust that cling to workers' clothes.

It is rare for asbestosis to develop in anyone who hasn't been exposed to large amounts of asbestos on a regular basis for at least 10 years. Symptoms of the disease do not usually appear until 15-20 years after initial exposure to asbestos.

The first symptom of asbestosis is usually shortness of breath following exercise or other physical activity. The early stages of the disease are also characterized by a dry cough and a generalized feeling of illness.

As the disease progresses and lung damage increases, shortness of breath occurs even when the patient is at rest. Recurrent respiratory infections and coughing up blood are common. So is swelling of the feet, ankles, or hands. Other symptoms of advanced asbestosis include chest pain, hoarseness, and restless sleep. Patients who have asbestosis often have clubbed (widened and thickened) fingers. Other potential complications include heart failure, collapsed (deflated) lung, and pleurisy (inflammation of the membrane that protects the lung).

Diagnosis

Screening of at-risk workers can reveal lung inflammation and lesions characteristic of asbestosis. Patients' medical histories can identify occupations, hobbies, or other situations likely to involve exposure to asbestos fibers.

X rays can show shadows or spots on the lungs or an indistinct or shaggy outline of the heart that suggests the presence of asbestosis. Blood tests are used to measure concentrations of oxygen and carbon dioxide. Pulmonary function tests can be used to assess a patient's ability to inhale and exhale, and a computed tomography scan (CT) of the lungs can show flat, raised patches associated with advanced asbestosis.

Treatment

The goal of treatment is to help patients breathe more easily, prevent colds and other respiratory infections, and control complications associated with advanced disease. Ultrasonic, cool-mist humidifiers or controlled coughing can loosen bronchial secretions.

Regular exercise helps maintain and improve lung capacity. Although temporary bed rest may be recommended, patients are encouraged to resume their regular activities as soon as they can.

Anyone who develops symptoms of asbestosis should see a family physician or lung disease specialist. A doctor should be notified if someone who has been diagnosed with asbestosis:

Key terms

Asbestos — A silicate (containing silica) mineral that occurs in a variety of forms; it is characterized by a fibrous structure and resistance to fire.

Prognosis

Asbestosis can't be cured, but its symptoms can be controlled. Doctors don't know why the health of some patients deteriorates and the condition of others remain the same, but believe the difference may be due to varying exposures of asbestos. People with asbestosis who smoke, particularly those who smoke more than one pack of cigarettes each day, are at increased risk for developing lung cancer and should be strongly advised to quit smoking.

Prevention

Workers in asbestosis-related industries should have regular x rays to determine whether their lungs are healthy. A person whose lung x ray shows a shadow should eliminate asbestos exposure even if no symptoms of the condition have appeared.

Anyone who works with asbestos should wear a protective mask or a hood with a clean-air supply and obey recommended procedures to control asbestos dust. Anyone who is at risk of developing asbestosis should:

asbestosis

asbestosis

Etymology: Gk, asbestos, inextinguishable, osis, condition

a chronic lung disease caused by the inhalation of asbestos fibers that results in the development of alveolar, interstitial, and pleural fibrosis. Asbestos miners and workers are most frequently affected, but the disease sometimes occurs in other people who have been exposed to asbestos building materials. Chest x-ray films show the characteristic small linear opacities distributed throughout the lungs. The disease is progressive: Shortness of breath develops eventually into respiratory failure. Cigarette smoking and continuous exposure to asbestos aggravate the condition. Fatal mesothelial tumors sometimes occur. There is no treatment. See also chronic obstructive pulmonary disease,inorganic dust.

Asbestosis

asbestosis

A condition characterised by diffuse pulmonary fibrosis caused by the inhalation of excessive amounts of asbestos fibres.

Clinical findingsAsbestosis is graded by severity of peribronchial fibrosis; fibres may not be found in the plaques.

DiffDx• Idiopathic pulmonary fibrosis (IPF)—Both have interstitial and basal subpleural fibrosis, but asbestosis has far less inflammation and far fewer fibroblastic foci, but usually has at least mild fibrosis of the visceral pleura, a feature rarely seen in IPF.• Respiratory bronchiolitis—Asbestosis is thought to begin in respiratory bronchioles and extend outward, increasingly involving lung acini until separate foci of fibrosis link, resulting in a diffuse pattern. Early disease is difficult to differentiate because similar centriacinar fibrosis is often seen in cigarette smokers and is characteristic of mixed-dust pneumoconiosis. Fibrosis limited to the walls of the bronchioles does not represent asbestosis.

Grading[▪ Grade—histologic changes.]▪ Grade 0—No appreciable peribronchiolar fibrosis, or fibrosis confined to the bronchiolar walls.▪ Grade 1—Fibrosis confined to the walls of respiratory bronchioles and the first tier of adjacent alveoli.▪ Grade 2—Extension of fibrosis to involve alveolar ducts and/or two or more tiers of alveoli adjacent to the respiratory bronchiole, with sparing of at least some alveoli between adjacent bronchioles.▪ Grade 3—Fibrotic thickening of the walls of all alveoli between at least two adjacent respiratory bronchioles.▪ Grade 4—Honeycomb changes.

An average score is obtained for an individual case by adding the scores for each slide (0 to 4), then dividing by the number of slides examined.

Grade 1 and to a lesser extent grade 2 need to be distinguished from smoking-induced peribronchiolar fibrosis and mixed dust pneumoconiosis.

asbestosis

Pulmonary medicine A condition characterized primarily by pleural fibrosis 2º to chronic inhalation of asbestos fibers Pathogenesis Asbestos fibers are phagocytosed by alveolar macrophages but, given their insoluble nature, the phagocytic vesicle bursts, releasing enzymes, killing the would-be killer Clinical Asbestosis is graded by severity of peribronchial fibrosis; fibers may not be found in the plaques. See Asbestos, Mesothelioma. Cf Coal workers' pneumoconiosis.

as·bes·to·sis

(as-bes-tō'sis)

Pneumoconiosis due to inhalation of asbestos fibers suspended in the ambient air; sometimes complicated by pleural mesothelioma or bronchogenic carcinoma.

asbestosis

A chronic lung disease caused by inhaling asbestos dust over a period. Thickening and scarring of the lung tissue occurs with reduced efficiency of oxygen and carbon dioxide interchange with the blood. The resulting breathlessness may progress to respiratory failure.

as·bes·to·sis

asbestosis

a disease of humans consistently exposed to asbestos fibers in the environment. Minimal pneumoconiosis found in ponies in coal mines. The human disease is marked by pulmonary fibrosis, pleural mesothelioma and pneumoconiosis.

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